P10.02 EFFECT OF INTEGRIN-EXTRACELLULAR MATRIX INTERACTIONS ON SMALL ARTERY STRUCTURE AND MECHANICS DURING HYPERTENSION AND AGING

Abstract

An age-related increase in systolic blood pressure and similarities in the consequences of hypertension and aging on arterial structure/mechanics have been reported, particularly in larger arteries. As the structural/mechanical properties of smaller resistance vessels in the context of advancing physiological age and the mechanisms underlying these parameters are less well defined, we studied the effect of disintegrin-treatment (kistrin, or echistatin), ex-vivo, on mesenteric artery structure and mechanics, using wire-myography, in 8 week-old (young), 15 week-old (adult) and >1 year-old (old) Spontaneously Hypertensive (SHRs) and Wistar-Kyoto rats (WKYs). Vascular integrin αV and α5 expression were also quantified. Initial narrowing of the lumen by inward eutrophic remodelling, in arteries from young and adult SHRs, was superseded by expansion of the lumen as a result of outward hypertrophic remodelling in old SHRs. Vascular stiffness was increased in young SHRs versus WKYs but was similar in adult and old SHRs versus WKYs, despite increased integrin αV and α5 expression in these latter two groups. Disintegrin-treatment of arteries did not alter structure or mechanics in SHRs. Aging in WKYs was associated with hypertrophic remodelling of mesenteric arteries which was independent of integrin expression and associated with no change in vascular stiffness. In WKYs at all ages, vascular structure remained unaltered by disintegrin-treatment; however, stiffness was significantly reduced with echistatin-treatment (P<0.05), suggesting that integrin-ECM interactions contribute towards passive stiffness of WKY arteries. Further insight into the influence of integrin-ECM interactions on vascular structure/mechanics will contribute towards a better understanding of hypertension and age-related cardiovascular complications.